Laser design

A laser gain element, comprising:

• an undoped layer of a monoclinic double tungstate (MDT) crystal;
• a layer of doped MDT crystal adjacent to the undoped layer, the doped MDT layer including a pre-selected concentration of rare earth ions;
• wherein
• the layer of doped MDT crystal has an absorption peak at a first wavelength and an emission peak at a second wavelength longer than the first wavelength;
• and
• the layer of doped MDT crystal has a fluorescence emission with a weighted average at a third wavelength shorter than the first wavelength,
• first facets formed on side edges of the layer of undoped MDT crystal, the first facets accepting normal incident pump light such that the pump light is reflected from a surface of the doped MDT crystal adjacent to the layer of undoped MDT crystal,
• a second facet formed on the side edges opposite each of the first facets of the layer of undoped MDT crystal such that light reflected from the surface of the doped MDT crystal that is received by a corresponding first facet is reflected by the second facet back to the first facet,
• wherein there are at least three first facets.